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Persicaria affinis (knot weed)

This mat-forming perennial with smooth leaves and spikes of small pink or red flowers was once admired in the Himalaya by Sir Joseph Hooker, one of Kew's early directors.
Illustration of knot weed

Detail of an illustration of Persicaria affinis

Species information

Scientific name: 

Persicaria affinis (D.Don) Ronse Decr.

Common name: 

knot weed, Himalayan fleece flower

Conservation status: 

Not evaluated according to IUCN Red List criteria.


Rocky mountainsides, screes, glacial moraines, alpine pastures, wet meadows and river banks.

Key Uses: 

Ornamental, traditional medicine.

Known hazards: 

Apparently distasteful to grazing animals.


Genus: Persicaria

About this species

This perennial forms mats that creep over rocks and steep slopes in the central Himalaya. The fresh green leaves emerge in spring and the flower spikes develop in late summer, bearing numerous, small pink or red flowers. After the first frosts, the leaves turn red then chestnut-brown.

One of Kew’s early directors, Sir Joseph Hooker, admired this species in the Himalaya, and described it ‘hanging in rosy clumps from moist precipices’.


Polygonum affine D.Don, Bistorta affinis (D.Don) Greene, Polygonum brunonis Wall.


main info

Courses at Kew

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Kew offers a variety of specialist training courses in horticulture, conservation and plant science.

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